Agassiz Research and Development Centre, Agriculture and Agri-Food Canada, 6947 Hwy 7, Agassiz, BC, V0M 1A0, Canada.
Department of Plant, Food and Environmental Sciences, Faculty of Agriculture, Dalhousie University, Truro, NS, B2N 5E3, Canada.
Appl Microbiol Biotechnol. 2024 Feb 26;108(1):237. doi: 10.1007/s00253-024-13040-6.
Late blight caused by Phytophthora infestans is an economically important disease of potato and tomato worldwide. In Canada, an increase in late blight incidence and severity coincided with changes in genetic composition of P. infestans. We monitored late blight incidence on tomato and potato in Pacific western and eastern Canada between 2019 and 2022, identified genotypes of P. infestans, and examined their population genetic diversity. We identified four major existing genotypes US11, US17, US8, and US23 as well as 25 new genotypes. The US11 genotype was dominant in Pacific western Canada, accounting for 59% of the total population. We discovered the US17 genotype for the first time in Canada. We revealed a higher incidence of late blight and quite diverse genotypes of P. infestans in Pacific western Canada than in eastern Canada. We found high genetic diversity of P. infestans population from Pacific western Canada, as evidenced by the high number of multilocus genotypes, high values of genetic diversity indices, and emergence of 25 new genotypes. Considering the number of disease incidence, the detection of diverse known genotypes, the emergence of novel genotypes, and the high number of isolates resistant to metalaxyl-m (95%) from Pacific western Canada, the region could play a role in establishing sexual recombination and diverse populations, which could ultimately pose challenges for late blight management. Therefore, continuous monitoring of P. infestans populations in Pacific western region and across Canada is warranted. KEY POINTS: • Genotypes of P. infestans in Pacific western were quite diverse than in eastern Canada. • We discovered US17 genotype for the first time in Canada and identified 26 novel genotypes. • Approximately 95% of P. infestans isolates were resistant to metalaxyl-m.
晚疫病由致病疫霉引起，是全球马铃薯和番茄的一种重要经济病害。在加拿大，晚疫病的发病率和严重程度的增加与致病疫霉遗传组成的变化相一致。我们在 2019 年至 2022 年期间监测了太平洋西部和东部加拿大的番茄和马铃薯晚疫病的发病率，鉴定了致病疫霉的基因型，并检查了它们的种群遗传多样性。我们鉴定了四个现有的主要基因型 US11、US17、US8 和 US23，以及 25 个新的基因型。US11 基因型在太平洋西部加拿大占主导地位，占总群体的 59%。我们首次在加拿大发现了 US17 基因型。我们发现太平洋西部加拿大的晚疫病发病率较高，致病疫霉的基因型也较为多样。我们发现太平洋西部加拿大的致病疫霉菌种群具有较高的遗传多样性，这表现在多基因座基因型数量较多、遗传多样性指数值较高以及 25 个新基因型的出现。考虑到疾病发病率的数量、已知多样基因型的检测、新基因型的出现以及来自太平洋西部加拿大的对金属增效醚（metalaxyl-m）具有抗性的分离物数量（95%），该地区可能在建立有性重组和多样化种群方面发挥作用，这最终可能对晚疫病管理构成挑战。因此，有必要在太平洋西部地区和加拿大各地持续监测致病疫霉菌种群。 关键点： • 太平洋西部的致病疫霉菌基因型比加拿大东部的更为多样。 • 我们首次在加拿大发现了 US17 基因型，并鉴定了 26 个新的基因型。 • 大约 95%的致病疫霉菌分离物对金属增效醚具有抗性。
